Perform network-specific host name resolutions using Network.getAllByName

Question

In the ConnectivityManager documentation, in bindProcessToNetwork javadoc, there is the following comment :

Using individually bound Sockets created by Network.getSocketFactory().createSocket() and performing network-specific host name resolutions via Network.getAllByName is preferred to calling bindProcessToNetwork.

In OkHttp, there is the setSocketFactory to satisfy the first part of the comment, but I have no idea how/where to use Network.getAllByName to perform the host name resolution.

Any idea how to perform that ?

Answer 1

Ok so I finally find out how to perform that. As I said in my question, I am using OkHttpClient to set my socketfactory. It is the same for the name resolution, using dns (it requires OkHttp3).

OkHttpClient.Builder httpBuilder = new OkHttpClient.Builder()
    .socketFactory(network.getSocketFactory())
    .dns(NetworkDns.getInstance())

where my NetworkDns class is looking to something like that

public class NetworkDns implements Dns {

  private static NetworkDns sInstance;
  private Network mNetwork;

  public static NetworkDns getInstance() {
    if (sInstance == null) {
      sInstance = new NetworkDns();
    }
    return sInstance;
  }

  public void setNetwork(Network network) {
    mNetwork = network;
  }

  @Override
  public List<InetAddress> lookup(String hostname) throws UnknownHostException {
    if (mNetwork != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
      return Arrays.asList(mNetwork.getAllByName(hostname));
    }
    return SYSTEM.lookup(hostname);
  }

  private NetworkDns() {
  }
}

This way, when network is not null, it will perform the host name resolution on the given network.